When transmitting AV information in digital form, there is a camera module as an important device used for the input and output of the information. Camera modules are mounted on mobile phones, laptop computers, digital cameras, digital video cameras and the like. For its photographing functions, a camera module may have a static still photographing function, as well as a dynamic monitoring function (for example, a rear monitor in an automobile etc.).
Until now, the plastic lenses of camera modules mounted on mobile phones have not been able to withstand solder reflow, which has prevented camera modules from being surface mounted (as a whole unit). Therefore, the substrate assembly step (onto a substrate) has either been carried out by surface mounting the module parts other than the lens portion, and then mounting the lens, or by assembling the whole camera module and mounting the camera module on the substrate by some other method.
Recently, inexpensive plastic lenses which are capable of withstanding solder reflow have been developed, giving rise to an environment in which surface mounting of the whole camera module can be carried out. Accordingly, liquid crystal polymers which have a high heat resistance and which can be molded in thinner wall-thickness are now being used for the “lens barrel portion” (section where the lens is placed), the “mount holder portion” (section in which the barrel is mounted and which is fixed to the substrate), the “CMOS (image sensor) frame,” and the “shutter and shutter bobbin portion” (refer to Patent Document 1).
For a typical camera module mounted with a fixed focus optical system, a CMOS (image sensor) has a structure in which a multilayer chip is mounted on a signal processing chip. In the assembly step of the CMOS, manual focus adjustment of the optical parts system becomes necessary (adjustment for optimizing the focus distance by threadedly moving the lens barrel portion screwed on a mount holder portion by a screw and by changing the distance between the lens and the image sensor) (Patent Document 1). However, for conventional liquid crystal polymer compositions, in this focus adjustment step, powders (particles) composed of the resin composition exfoliate from the lens barrel, the portions where both the mount holder and lens barrel wear against each other during screwing, and the surfaces of both molded articles during the threaded movement of the lens barrel portion. These powders land on the CMOS (image sensor) or on an (IR cutting) filter, thereby becoming one of large causes to induce image defects. Powder exfoliation can also occur during use of a product in which these members are built. Therefore, as the material used for the lens barrel portion, mount holder portion, CMOS (image sensor) frame, shutter, shutter bobbin portion and the like of camera modules, there is a need to provide a liquid crystal polyester composition having a low level of powder (particle) exfoliation.
As the material used for the above-described camera module part, although several further examples using a liquid crystal polymer can be cited in addition to Patent Document 1 (Patent Documents 2 and 3), none of these examples touches on a method for controlling the occurrence of powders (particles) during the assembly step as described above, or on the development of a resin composition in which there is little occurrence of powder (particle) exfoliation.
To improve the mechanical properties, anisotropy, warpage, and heat resistance of a liquid crystal polyester resin, it is known to add a plate-like substance such as talc and a fibrous substance such as a glass fiber. Although strength and elastic modulus improve by adding a fibrous substance such as a glass fiber, there is the drawback that the effect of an improvement in anisotropy is small. Although anisotropy improves by adding a plate-like substance such as talc, there is the drawback that the effects of an improvement in the strength and elastic modulus are small. Therefore, attempts are being made to improve the balance between strength and elastic modulus, anisotropy and the like by adding the fibrous substance such as a glass fiber and the plate-like substance such as talc in various combinations (for example, refer to Patent Documents 4 to 8). In addition, although there are also documents which discuss the surface appearance of such a molded article (refer to Patent Document 9), the document is completely silent about a preferred plate-like substance such as talc, and fibrous substance such as a glass fiber relating to the production of a resin composition having such strict surface transferability—reducing as much as possible the occurrence of exfoliations of the surface—of a molded article as in the present usages.    Patent Document 1: Japanese Patent Application Laid-Open No. 2006-246461    Patent Document 2: Japanese Patent Application Laid-Open No. 2008-028838    Patent Document 3: Japanese Patent Application Laid-Open No. 2008-034453    Patent Document 4: Japanese Patent Application Laid-Open No. Hei 04-76049    Patent Document 5: Japanese Patent Application Laid-Open No. Hei 10-219085    Patent Document 6: Japanese Patent Application Laid-Open No. 2000-178443    Patent Document 7: Japanese Patent Application Laid-Open No. 2002-294038    Patent Document 8: Japanese Patent Application Laid-Open No. 2003-246923    Patent Document 9: Japanese Patent Application Laid-Open No. 2003-128895